Note: Descriptions are shown in the official language in which they were submitted.
CA 022~982 1998-12-14
TITLE OF THE INVENTION
MOLDED ELECTRICAL SWITCH
CROSS-REFERENCE TO RELATED APPLICATIONS
Not Applicable
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR
DEVELOPMENT
Not Applicable
FIELD OF INVENTION
15The present invention relates generally to electrical
switches and, more particularly, to a molded electrical
switch that can be produced in high volumes with a minimum
number of fabrication steps.
20BACKGROUND OF THE INVENTION
The use of electrical switches is widespread in the
present electronic age. Simple electrical switches are used
for a variety of purposes ranging from household appliances
25to complex computer circuitry. These simple electrical
switches must be inexpensive to manufacture and must be
produced in large quantities to fill large demands.
To date, most simple electrical switches are fabricated
with separate molded non-conductive components and conductive
30contact elements. These molded non-conductive components and
conductive elements are typically assembled together at some
time after the molded components have cured. Thus, at least
two fabrication steps are required for these simple
electrical switches: a molding step and an assembling step.
CA 022~982 1998-12-14
Furthermore, there are currently no electrical switches
available which have a conductive elastomer grafted directly
to a molded non-conductive component thereof. Such a
conductive elastomer could provide an conducting contact
surface for an electrical switch. Additionally, the
conductive elastomer could be grafted to the molded non-
conductive component of the electrical switch during the
processing of the molded non-conductive component of the
electrical switch, thereby shortening or eliminating a
fabrication step.
In view of the foregoing, it would be desirable to
provide a molded electrical switch that can be produced in
high volumes with a minimum number of fabrication steps.
SUMMARY OF THE INVENTION
The present invention contemplates several types of
electrical switches. In one embodiment, the present
invention is realized as an electrical switch comprising: a
molded case having a pair of conductive terminal contacts;
and a molded actuator for mating with the case, wherein the
actuator is movable between a conducting position and a non-
conducting position within the case, wherein the actuator has
at least one spring member and a conductive contact surface,
wherein the spring member forces the actuator into the non-
conducting position, and wherein the conductive contact
surface provides an electrical connection between the pair
of conductive terminal contacts when the actuator is in the
conducting position. The actuator is retained within the
case by a retaining member and/or a snap member. The case
and the actuator are molded about the conductive terminal
contacts and the spring members, respectively. Furthermore,
the conductive contact surface is formed of a conductive
CA 022~982 1998-12-14
elastomer that is grafted to the actuator.
In other embodiments, the spring members are molded as
5a part of the actuator or the case, or the spring members are
connected to the conductive contact surface or the conductive
terminal contacts with the actuator and the case being molded
thereabout, respectively. Further embodiments are also
disclosed.
10In view of the foregoing, it is quite apparent that the
present invention overcomes the shortcomings of the above-
mentioned prior art, and that the primary object of the
present invention is to provide molded electrical switch that
can be produced in high volumes with a minimum number of
15fabrication steps.
The above-stated primary object, as well as other
objects, features, and advantages, of the present invention
will become readily apparent from the following detailed
description which is to be read in conjunction with the
20appended drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
In order to facilitate a fuller understanding of the
25present invention, reference is now made to the appended
drawings. These drawings should not be construed as limiting
the present invention, but are intended to be exemplary only.
Figure 1 is a top perspective view of an actuator for
a two-piece pushbutton switch in accordance with the present
30invention.
Figure 2 is a bottom perspective view of the actuator
shown in Figure 1.
Figure 3 is a top perspective view of a case for a two-
piece pushbutton switch in accordance with the present
CA 022~982 1998-12-14
invention.
Figure 4 is a side cross-sectional view of the case
shown in Figure 3.
Figure 5 is an exploded assembly view of the actuator
and case shown in Figures 1 and 2 and Figures 3 and 4,
respectively.
Figure 6 is top perspective view of a two-piece
pushbutton switch 50 in accordance with the present
lnvent lon .
Figure 7 is a top view of a frame of a double-railed
molding assembly for a one-piece molded switch in accordance
with the present invention.
Figure 8 is a top view of a frame of a double-railed
molding assembly for two-piece molded switches in accordance
with the present invention.
Figure 9 is a side cross-sectional view of one of the
actuators shown in Figure 8.
Figure 10 is a bottom perspective view of an alternate
embodiment actuator for a two-piece pushbutton switch in
accordance with the present invention.
Figure 11 is a top perspective view of the alternate
embodiment actuator shown in Figure 10.
Figure 12 is a bottom view of a plurality of the
alternate embodiment actuator shown in Figure 10 being held
together by a runner system.
Figure 13 is a top perspective view of an alternate
embodiment case for a two-piece pushbutton switch in
accordance with the present invention.
Figure 14 is a side cross-sectional view of the
alternate embodiment case shown in Figure 13.
Figure 15 is a top view of an alternate embodiment
molding assembly die for use in fabricating the case shown
in Figures 13 and 14.
Figure 16 is a side perspective view of an alternate
CA 022~982 1998-12-14
embodiment molding assembly die for use in fabricating the
case shown in Figures 13 and 14.
Figure 17 is an exploded assembly view of the actuator
and case shown in Figures 10 and 11 and Figures 13 and 14,
respectively.
Figure 18 is top perspective view of a two-piece
pushbutton switch in accordance with the present invention.
Figure 19 is a cross-sectional view of an alternate
embodiment two-piece pushbutton switch in accordance with the
present invention.
Figure 20 is a perspective view of a conductive terminal
contact for use in a pushbutton switch in accordance with the
present invention.
Figure 21 is a perspective view of a conductive terminal
contact having a beam spring member for use in a pushbutton
switch in accordance with the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Referring to Figures 1 and 2, there are shown top and
bottom perspective views, respectively, of an actuator 10 for
a two-piece pushbutton switch in accordance with the present
invention. The actuator 10 comprises a main body portion 12,
an elevated finger button 14, a pair of retaining members 16,
a pair of spring members 18, and a conductive contact 20.
The main body portion 12 is sized to mate with a
corresponding case (see Figures 3-6) for the two-piece
pushbutton switch. The pair of retaining members 16 are
sized to mate with corresponding guides (see Figures 3-6)
within the case for the two-piece pushbutton switch. The
elevated finger button 14, and hence the entire pushbutton
switch, is sized for actuation by a human finger. The main
body portion 12, the elevated finger button 14, and the pair
of retaining members 16 are preferably all fabricated of the
CA 022~982 1998-12-14
same material and from a single mold. A liquid crystal
polymer (LCP) known by the trade name VECTRA~ may be used for
the molded material, particularly because of its high melting
point. Of course, other materials may also be used.
The pair of spring members 18 provide reverse actuation
force against the case for the two-piece pushbutton switch.
The spring members 18 may be fabricated of the same material
and from the same mold as the main body portion 12, the
elevated finger button 14, and the pair of retaining members
16, or the spring members 18 may be formed of resilient metal
with the molded main body portion 12 providing support
therefor.
The conductive contact 20 provides a conductive contact
surface for bridging between two corresponding conductive
contacts in the case for the two-piece pushbutton switch (see
Figures 3-6). The conductive contact 20 is preferably
fabricated of a conductive elastomer which may be grafted
directly to the underside of the main body portion 12. The
conductive elastomer may have conductive particles along its
surface so as to pierce through any oxide which may have
formed on the two corresponding conductive contacts in the
case for the two-piece pushbutton switch. Alternatively, the
conductive contact 20 may be formed of metal with the molded
main body portion 12 providing support therefor.
Referring to Figures 3 and 4, there are shown a top
perspective view and a side cross-sectional view,
respectively, of a case 30 for a two-piece pushbutton switch
in accordance with the present invention. The case 30
comprises a hollowed structure 32 having a pair of apertures
34 formed in opposite ends thereof for mating with the
retaining members 16 of the actuator 10 (see Figures 1 and
2). Bordering each aperture 34 is a pair of guides 36 for
guiding the retaining members 16 toward the apertures 34.
A protrusion 38 is formed in the center of the case 30 for
CA 022~982 l998- l2- l4
supporting a pair of conductive terminal contacts 40.
Similar to the actuator 10, the case 30, including the
hollowed structure 32, the guides 36, and the protrusion 38,
is preferably fabricated of an LCP in a single mold. The
conductive terminal contacts 40 are preferably fabricated of
a copper alloy material, although other materials may also
be used.
Referring to Figure 5, there is shown an exploded
assembly view of the actuator 10 and the case 30 for a two-
piece pushbutton switch in accordance with the present
invention.
Referring to Figure 6, there is shown a top perspective view
of a two-piece pushbutton switch 50 in assembled form in
accordance with the present invention.
Referring to Figure 7, there is shown a top view of a
frame of a double-railed molding assembly 60 for a one-piece
molded switch in accordance with the present invention. The
molding assembly 60 comprises two metal rails 62 each having
apertures 64 formed therein for mating with a sprocket wheel
(not shown). The sprocket wheel engages the apertures 64 in
order to move the molding assembly 60 toward and/or away from
an injection molding machine (not shown). The molding
assembly 60 also comprises cross members 66 for maintaining
the spacing between the two metal rails 62.
Extending off one of the metal rails 62 are leads 68 for
the conductive terminal contacts 40. The leads 68 are cut
away from the conductive terminal contacts 40 when the one-
piece molded switch is to be used.
Extending off the other metal rail 62 iS a metal support
member 70 for supporting the actuator 10 through a
corresponding molded support member 72. This molded support
member 72 iS trimmed or broken off when the one-piece molded
switch is to be used. Another molded support member 74
provides a connection between the actuator 10 and the case
CA 022~982 l998- l2- l4
30. This molded support member 74 iS flexible so as to allow
the actuator 10 to be folded over into the case 30 when the
one-piece molded switch is to be used, thereby fully
assembling the one-piece molded switch.
All of the other elements of the molding assembly 60
are similar to those shown and described in Figures 1-6, and
thus those elements are similarly numerically designated.
This includes the spring members 18, which in this embodiment
are fabricated of the same material and from the same mold
as the main body portion 12 of the actuator 10, and the
conductive contact 20, which in this embodiment is fabricated
of a conductive elastomer grafted directly to the underside
of the main body portion 12 of the actuator 10.
The grafting of the conductive elastomer takes place after
the molded material has cured.
Referring to Figure 8, there is shown a top view of a
frame of a double-railed molding assembly 80 for two-piece
molded switches in accordance with the present invention.
The molding assembly 80 comprises elements that are similar
2 0 to those shown and described in Figure 7, and thus those
elements are similarly numerically designated. The molding
assembly 80 also comprises new and additional elements
including alternate embodiment actuators 82. Each actuator
82 iS connected to one of the metal rails 62 by metal support
members 84 which are also used to provide resilient metal
spring members 86 and a conductive contact 88. A main body
portion 90 is molded around the metal support members 84, and
the metal support members 84 are cut away from the main body
portion 90 when the actuator 82 is to be used. Similar to
the actuator 10 shown in Figures 1 and 2, each actuator 82
has retaining members 16.
It should be noted that the molding assembly 80 may be
divided into two separate molding assemblies by removing the
cross members 66. This may be desirable since having two
-
CA 022~982 1998-12-14
separate molding assemblies would allow the actuators 82 and
the cases 30 to be separately fabricated. It would also
decrease the complexity of the die set and mold used in the
single molding assembly 80.
Referring to Figure 9, there is shown a side cross-
sectional view of one of the actuators 82 shown in Figure 8.
From this view, it can be seen that the resilient metal
spring members 86 are initially in an upright position, but
can be bent in the respective directions 92 and 94 so as to
be functional when the actuator 82 is mated with a case 30.
Referring to Figures 10 and 11, there are shown bottom
and top perspective views, respectively, of another alternate
embodiment actuator 100 for a two-piece pushbutton switch in
accordance with the present invention. The actuator 100
comprises a main body portion 102, an elevated finger button
104, a pair of retaining members 106 formed into main body
portion 102, and a conductive contact 108. The main body
portion 102 is sized to mate with a corresponding case (see
Figures 13, 14, 17, and 18) for the two-piece pushbutton
switch. The pair of retaining members 106 are sized to mate
with corresponding snap members (see Figures 13, 14, 17, and
18) within the case for the two-piece pushbutton switch. The
main body portion 102, the elevated finger button 104, and
the pair of retaining members 106 are preferably all
fabricated of the same material and from a single mold. As
with the case of the actuator 10 shown in Figures 1 and 2,
the LCP known by the trade name VECTRATM may be used for the
molded material. Of course, other materials may also be
used.
The conductive contact 108 provides a conductive contact
surface for bridging between two corresponding conductive
contacts in the case for the two-piece pushbutton switch (see
Figures 13, 14, 17, and 18). The conductive contact 20 is
preferably fabricated of a conductive elastomer which may be
CA 022~982 1998-12-14
-10 -
grafted directly to the underside of the main body portion
12. The conductive elastomer may have conductive particles
along its surface so as to pierce through any oxide which may
have formed on the two corresponding conductive contacts in
the case for the two-piece pushbutton switch.
Referring to Figure 12, there is shown a bottom view of
a plurality of the alternate embodiment actuators 100 being
held together by a runner system 110. The actuators 100 and
the runner system 110 are created by a mold which allows
molding material such as VECTRA~ to flow along various
channels formed in the mold. After drying, the molding
material forms the pattern shown in Figure 12. Also after
drying, the conductive contacts 108 are grafted directly to
the underside of the actuators 100. The individual actuators
100 are then cut away from the runner system 110 as needed.
Referring to Figures 13 and 14, there are shown a top
perspective and a side cross-sectional view, respectively,
of an alternate embodiment case 120 for mating with the
actuator 100 shown in Figures 10-12. The case 120 comprises
a hollowed structure 122 having a pair of snap members 124
formed in opposite ends thereof for mating with the retaining
members 106 of the actuator 100 (see Figures 10 and 11). A
protrusion 38 is formed in the center of the case 120 for
supporting a pair of conductive terminal contacts 40. A pair
of protrusions 126 (only one shown) are also formed along the
side edges of the case 120 for providing a stop when the
actuator 100 is depressed. Both of the conductive terminal
contacts 40 are extended to provide a pair of spring members
128 (only one shown), as described in more detail below.
Similar to the actuator 100, the case 120, including the
hollowed structure 122 and the protrusions 38 and 126, is
preferably fabricated of an LCP in a single mold. The
conductive terminal contacts 40, including the spring members
128 are preferably fabricated of a copper alloy material,
CA 022~982 1998-12-14
although other materials may also be used.
Referring to Figures 15 and 16, there are shown a top
and a side perspective view, respectively, of an alternate
embodiment molding assembly die 130 for use in fabricating
the case 120 shown in Figures 13 and 14. Similar to the
molding assembly 60, the molding assembly die 130 comprises
two metal rails 62 each having apertures 64 for mating with
a sprocket wheel, and cross members 66 for maintaining the
spacing between the two metal rails 62. Extending off each
metal rail 62 are leads 132 for the conductive terminal
contacts 40. As previously described, both of the conductive
terminal contacts 40 are extended to provide the pair of
spring members 128. These type of spring members 128 can be
referred to as beam spring members.
Referring to Figure 17, there is shown an exploded
assembly view of the actuator 100 and the case 120 for a two-
piece pushbutton switch in accordance with the present
invention. Referring to Figure 18, there is shown a top
perspective view of a two-piece pushbutton switch 140 in
assembled form in accordance with the present invention.
Referring to Figure 19, there is shown a cross-sectional
view of a further alternate embodiment two-piece pushbutton
switch 150 in accordance with the present invention. Similar
to the previously described embodiments, the two-piece
pushbutton switch 150 comprises a mating actuator 152 and
case 154. The actuator 152 has a conductive contact 156
disposed on its underside, and the case 154 has a conductive
terminal contacts 158 formed therein. The case 154 also has
a protrusion 160 formed in the center thereof, and two
openings 162 are formed in the protrusion 160 extending from
the top of the protrusion down to the conductive terminal
contacts 158. A barrel-shaped conductive column 164 is
disposed within each opening 162 so as to provide an
electrical connection between the conductive terminal
CA 022~982 l998- l2- l4
-12 -
contacts 158 and the conductive contact 156 when the actuator
152 iS depressed. The conductive columns 164 are preferably
fabricated of a conductive elastomer. The conductive columns
164 may have conductive particles along their surfaces so as
to pierce through any oxide which may have formed on either
the conductive terminal contacts 158 and/or the conductive
contact 156.
A spring member 166 iS located on each side of the case
154. The spring members 166 may be of the beam spring type
as described above, or another type of spring member may be
used such as a coil spring. If a coil spring were to be
used, the shape of the conductive terminal contact 158 could
be as shown in Figure 20. Figure 21 shows a conductive
terminal contact 168 having a beam spring member 170. This
conductive terminal contact 168 has a shape that is slightly
different than those that have heretofore been described.
It should be noted that all of the conductive terminal
contacts that have heretofore been described have two
parallel leads for purposes of coplanarity. The parallel
leads also allow the switches to sit flat on a circuit board
before soldering. Of course, conductive terminal contacts
having single leads may also be used in accordance with the
present invention.
The present invention is not to be limited in scope by
the specific embodiments described herein. Indeed, various
modifications of the present invention, in addition to those
described herein, will be apparent to those of skill in the
art from the foregoing description and accompanying drawings.
Thus, such modifications are intended to fall within the
scope of the appended claims.
